#include <stdio.h>
#include <pthread.h>

int sum=0;
pthread_mutex_t mutex;

void *thread(void*){
	int i;
	for (i=0;i<1000000;i++){
		pthread_mutex_lock(&mutex);
		sum+=1;
		pthread_mutex_unlock(&mutex);
	}
}

int main(void){
	pthread_t tid1,tid2;
	pthread_mutex_init(&mutex,NULL);
	
	pthread_create(&tid1,NULL,thread,NULL);
	pthread_create(&tid2,NULL,thread,NULL);
	pthread_join(tid1,NULL);
	pthread_join(tid2,NULL);
	printf("1000000+1000000=%d\n",sum);
	return (0);
}
